It is generally known for a silver-containing catalyst to be employed in the preparation of ethylene oxide. See for example British patent specification 1,413,251 and also the literature cited therein. In order to obtain improved silver catalysts, efforts have been directed for many years towards modifying the silver catalysts with the aid of promoters. For example, the above-mentioned British patent specification 1,413,251 describes a process in which a silver compound is applied to a carrier, after which the applied silver compound is reduced to silver and in which additionally a promoter in the form of potassium oxide, rubidium oxide or cesium oxide or a mixture thereof is present on the carrier.
Applicant has found a silver catalyst with improved selectivity and a high stability and activity.